1. Field of the invention
This invention relates to mixing apparatus and, more particularly, to a portable mixing apparatus in which aggregate and or cementitious material, water, and additive material may be maintained separately from each other at a job site until it is desired that the ingredients be mixed together in a desired blend and quantity.
2. Description of the Prior Art
U.S. Pat. No. 4,855,960 (Janssen et al) discloses a silo apparatus in which cementitious material and aggregate may be mixed at a job site. The silo may be transported to a job site on a trailer and then the mixer is removed from the trailer and left at the job site, freeing the trailer for further use. The silo includes separate compartments for cementitious material and for aggregate. The cementitious material, and aggregate and water are appropriately blended and mixed at the job site.
The silo concept may be suitable for large construction jobs where a substantial amount of the desired product is needed. However, such is not practical for small or medium sized construction jobs.
The alternative to a silo is simply the common mixer which is hauled to the job site, along with aggregate and cementitious material, etc.
One of the problems with prior art apparatus is the wide variation in quantities of aggregate conveyed by augers, such as in the '960 (Jansen et al) apparatus to be mixed with cementitious material. The problem stems from aggregate falling onto the auger and past the auger directly into the mixing chamber. The aggregate thus essentially bypasses the auger and the quantitative control afforded by the auger.
The problem discussed in the preceding paragraph is alleviated in the present invention by the provision of a metering sleeve adjacent to the mixing chamber and over and around or about a portion of the auger. The metering sleeve insures that the aggregate is metered to the mixing chamber by the auger.
The apparatus of the present invention overcomes the shortcomings of the prior art by providing a portable, trailer mounted unit in which the basic ingredients of aggregate and or cementitious may be placed in separate compartments and the unit may then be hauled to a construction site by a pickup truck. At the site, a suitable water supply may be connected to the unit and the cementitious material and aggregate and water may be appropriately mixed as desired. The product is accordingly only mixed as needed, and the dry ingredients may be maintained indefinitely until the mixed product, stucco, plaster, grout, etc., is needed.
The basic ingredients of aggregate and or cementitious material will be referred to herein. It will be obvious that other ingredients may be added to the basic ingredients in accordance with the desired product. Such is well known and understood in the art.